The Present Disclosure relates generally to fluid sensors, and, in particular, to sensors that have a flexible body for application to fluid containers of varying configurations, as well as sensors that have improved sensor capabilities.
Fluid sensors are used in a variety of applications. Their usage in the medical arts has grown, and sensors are used in association with biopumps that remove a certain volume of fluid from a body location, with containers such as beakers, columns and drip bags, to measure predetermined levels of fluid for infusion into the body. Other applications are known, and many of these fluid containers have irregularly-shaped exterior configurations, making it difficult to read the measurements scribed on their sides. Optical measurement indicia, such as graduated lines, are hard to difficult to read in an automated manner, and are not conducive to fast timing diagnostic and other procedures. Hence, fluid sensors were developed that may be attached to containers and which can provide readout signals that may be displayed, or otherwise read, by a monitoring device.
Such a fluid sensor is described in U.S. Pat. No. 6,490,920, issued 10 Dec. 2002, the content of which is hereby incorporated herein in its entirety. The sensor described in the '920 patent utilizes a flexible substrate that supports a series of conductive members disposed on a surface of the substrate and are arranged to form a single sensor with multiple, interacting members, more in the form of appendages that extend in opposite directions from a baseline of each such member. These appendages are interlaced with each other so that they appear as a series of fingers that extend into gaps between adjacent fingers of an opposite member. As such, each member of the sensor of the '920 patent constitutes one single and elongated sensor member. The large length of this sensor reduces its ability to accurately, at very small tolerances measure fluid levels. Although it is suitable for a gross measurement, it is difficult to obtain very fine tolerance fluid level readings. The Present Disclosure is therefore directed to an improved fluid sensor better suited for capacitively measuring fluid levels in containers, and particularly irregularly shaped containers.